The single column tie is called like that because it’s used to tie a “column”, meaning a wrist, a leg, an ankle, the bust, but also for example two arms like this, since they make a “single column” anyway. This tie is also often used in more elaborate structures.

This video was made for the new edition of Ayzad’s “I love BDSM” that you can find here:
By the same author I suggest you also: “BDSM”